<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
        <script src="./vue.js"></script>
    </head>
    <body>
        <div id="app">
            <h2>{{msg}}</h2>
            <!-- v-once 不需要表达式  只渲染元素和组件一次 -->
            <h2 v-once>{{msg}}</h2>
        </div>
    </body>
    <script>
        let app = new Vue({
            el:"#app",
            data:{
                msg:"李银河"
            }
        })

    </script>
</html>